1. Field of the Invention
The present invention relates to a fire receiver for indicating a condition of a building, an occurrence of fire or a gas leakage, etc.
2. Description of the Related Art
A conventional fire receiver used in a fire alarm equipment, when fire sensors provided at various places of the building detect fire, indicates on a display unit the corresponding section of the building that is on fire and sounds an alarm to thereby provide visible and audible warnings of the fire. There are two main systems for indicating a section on fire: a fire section indicating system in which a number or a character indicating a section on fire is given by using a so-called seven segment display or a liquid crystal display (LCD), and a section window indicating system in which all the windows corresponding to monitoring sections set in the building are formed in a single or a plurality of display units and in which an indicating lamp that indicates an action such as fire is provided for each window.
In the section window indicating system, all the monitoring sections set in the building have to be formed as windows, each window indicating the name of the corresponding section, etc. Thus, usually there is provided a window sheet to be fitted into the window frame and the window sheet in which the information is completed is held under a transparent protective sheet. If the use of the section is changed to cause a change in its name, etc., it is only necessary to replace the window sheet fitted into the window frame.
The display unit of such a section window indicating system is used not only in a fire receiver, but also in a fire annunciator that indicates the position of fire. Apart from this, it is used in various display units for indicating, e.g., a floor on which a fire extinguishing equipment with sprinklers is working, or a monitoring section in which a security system is operating.
Next, a casing of a conventional fire receiver will be described.
FIGS. 16 and 17 are diagrams illustrating an example of a conventional fire receiver. FIG. 16 is a front view showing a panel surface, and FIG. 17 is a front view with its door open.
Connected to the fire receiver is a line (not shown) equipped with a terminal apparatus such as a fire sensor. As shown in FIG. 17, there are provided in a box-like main body 3 a main operating portion 10 connected to the line and adapted to perform various settings on the terminal apparatus, etc., and eight display units 21a through 21e and 22f through 22h connected to the main operating portion 10 and adapted to indicate the conditions, etc. of the terminal apparatuses. Further, provided in a door 4 forming the main body 3 are a main opening 5 and openings 41a through 41e and 42f through 42h in correspondence with an indicating portion 10A of the main operating portion 10 and indicating portions 31a through 31e and 32f through 32h of the display units 21a through 21e and 22f through 22h. Mounted to the door 4 are a main transparent protective plate 7 and transparent protective plates 51a through 51e and 52f through 52h so as to cover the main opening 5 and the openings 41a through 41e and 42f through 42h. 
With this structure, the outer side of the fire receiver is covered with a casing 40 formed by the box-like main body 3 equipped with the door 4 and the main transparent protective plate 7 and the transparent protective plates 51a through 51e and 52f through 52h mounted to the door 4, whereby intrusion of dust or the like into the interior is prevented. Normally, the fire receiver is locked with the door 4 closed so that the main operating portion 10, etc. may not be operated, and the indication on the main operating portion 10 and the display units 21a through 21e and 22f through 22h can be visually checked from outside the casing 40 through the main transparent protective plate 7 and the transparent protective plates 51a through 51e and 52f through 52h. 
The above-mentioned conventional fire receiver, however, involves the following problems. In the display unit of the section window indicating system, it is desirable for the window sheet, to which the section name, etc. are written, to be easily replaced and to be of a simple structure in which it is easily detachable.
Further, as shown in FIG. 17, the casing 40 allows, for example, provision of five display units on the right-hand side and three display units on the left-hand side, i.e., eight display units in total. However, the number of display units required varies depending on the building in which the system is installed. Thus, for the casing of a conventional fire receiver, a number of kinds of doors with different numbers of openings are prepared, and an arbitrary door corresponding to the requisite display units for the building is used. This arrangement is adopted to enable the person on guard monitoring the fire receiver or the like installed in a building or the like to check the indication of the display units at a glance. If there is an opening corresponding to a display unit not provided in the casing, and the interior of the casing can be observed therethrough, the checking operation becomes the more complicated. Further, for a better outward appearance, it is desirable to eliminate an opening corresponding to a display unit not provided in the casing so that the interior of the casing cannot be observed through such an opening. This leads to an increase in parts cost and makes the stock control in the plant and the shipping difficult to perform. Further, when the number of display units is to be increased or decreased after installation, the door has to be replaced.
The present invention has been made in view of the above, and an object of the present invention is therefore to simplify the structure of a section window of a display unit for use in the section indicating system to thereby facilitate the replacement of the window sheet.
Another object of the present invention is to provide a casing for use in a fire receiver or the like in which display units provided in the casing can be visually checked from outside, in which one type of door can be applied to buildings requiring different numbers of display units.
According to a first aspect of the present invention, there is provided a fire receiver in which a building is divided into sections for each of which window indication is made by using a corresponding window. The fire receiver comprises: a base having a frame for window indication; a rectangular window sheet to which the names of the sections are written and which is fitted into the frame of the base; and a rectangular substantially transparent protective sheet which is substantially of the same configuration as the window sheet and arranged in front of it and has at its longitudinal ends engagement members to be engaged with engagement grooves of the frame and at its center a central engagement member to be engaged with a central engagement groove of the frame.
Preferably, in the fire receiver, the window sheet corresponds to a plurality of sections and consists of a rectangular sheet longitudinally divided into a plurality of portions to which the names of the sections can be written. In addition, preferably, indicating lamps are provided in correspondence with the sections.
According to a second aspect of the present invention, there is provided a fire receiver comprising: a main body in which a plurality of display units are provided; a door mounted to the main body so as to be capable of opening and closing, a plurality of openings being formed in advance in the door in correspondence with the positions where the display units can be provided in the main body; transparent protective means mounted to the door and adapted to cover the plurality of openings; and opaque covering means attached to positions corresponding to the plurality of openings on the transparent protective means and separable from each opening.
Preferably, in the fire receiver, the opaque covering means consists of a plurality of opaque seals separable from the openings corresponding to the positions where the display units are actually provided in the main body. In addition, preferably, the transparent protective means comprises at least one transparent protective plate, and the one transparent protective plate collectively covers a plurality of the openings provided in a row in the door.
According to another second aspect of the present invention, there is provided a fire receiver comprising: a main body in which a plurality of display units are provided; a door mounted to the main body so as to be capable of opening and closing, a plurality of openings being formed in advance in the door in correspondence with the positions where the display units can be provided in the main body; and protective means consisting of a plurality of plates selected from a plurality of transparent protective plates and a plurality of opaque protective plates and mounted to the door to cover the plurality of openings.
According to another second aspect of the present invention, there is provided a fire receiver comprising: a main body in which a plurality of display units are provided; a door mounted to the main body so as to be capable of opening and closing, a plurality of knock-out portions capable of forming a plurality of openings being provided in the door in correspondence with the positions where the display units can be provided in the main body; and transparent protective means for covering at least one of the openings formed in the door.
Preferably, in the fire receiver, the opaque covering means and the opaque protective plates are substantially the same color as the door. In addition, preferably, the display units respectively make window indication using windows corresponding to sections into which a building is divided and the window consists of a base having a frame for window indication and a rectangular window sheet to which the names of the sections are written and which is fitted into a frame of the base and a rectangular substantially transparent protective sheet which is substantially of the same configuration as the window sheet and arranged in front of it and has at its longitudinal ends engagement members to be engaged with engagement grooves of the frame and at its center a central rectangular engagement member to be engaged with a central engagement groove of the frame.